JPH10239006A - Touch signal probe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a touch signal probe having a simple structure and no direction dependency. SOLUTION: The sum of the output signals outputted from piezoelectric elements 21 , 22 ,..., 2n fitted on the side face of a piezoelectric element support section having a regular n-polygonal cross section is obtained by the first adding circuit 31, and this sum is multiplied by 1/n by the first amplifying circuit 32 to obtain an average value. The voltage that the absolute value of the output of the first amplifying circuit 32 becomes the maximum is kept in the first peak hold circuit 36, and the differences between the output signals outputted from the piezoelectric elements 21 , 22 ,..., 2n and the output of the first amplifying circuit 32 are obtained by the first subtracting circuit 34. The voltage that the absolute value of the output of the first subtracting circuit 34 becomes the maximum is kept in the second peak hold circuit 37, and contact directions α, β and velocity V are detected by a contact state detecting circuit 38 from the voltages kept in the peak hold circuits 36, 37.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a touch signal probe used for measuring the shape and the like of an object to be measured by a coordinate measuring machine or the like.

[0002]

2. Description of the Related Art A three-dimensional measuring machine or the like is known as a measuring machine for measuring the shape and dimensions of an object to be measured, but a stylus is used for measuring coordinates and position in such a case. A touch signal probe is provided that has a spherical contact portion at the tip of the sensor and detects that the contact portion has come into contact with an object to be measured. Conventional example of touch signal probe is Japanese Patent Publication No. 60-486
No. 81 (conventional example 1), JP-A-54-78164 (conventional example 2) and JP-A-8-327308 (conventional example 3).

In Conventional Example 1, a measuring head or a measuring probe comprises a movable portion and a fixed portion, which are connected to each other via a seating mechanism. The movable part is composed of two divided members, and a measuring element (piezoelectric element) that responds to tension and compression with high sensitivity is provided between these members. In Conventional Example 2, a piezoelectric element is incorporated in a part of a stylus, a stylus is divided into two parts, a piezoelectric element is sandwiched between the divided styluses, and a piezoelectric element is attached to a contact portion provided at the tip of the stylus. It is a structure in which the element is worked up, and furthermore, the piezoelectric element is interposed between the contact portion and the stylus. In Conventional Example 3, a stylus is attached to the center of a disk-shaped substrate, and a plurality of piezoelectric elements are radially arranged around the stylus. In order to detect that the stylus has contacted the object to be measured, the sum of the absolute values of the signals output from the respective piezoelectric elements is detected.

[0004]

In the conventional examples 1 and 2,
When installing one piezoelectric element, when installing multiple piezoelectric elements, etc.
Various cases are disclosed. In general, the smaller the number of piezoelectric elements, the simpler the stylus structure and the easier the assembling, has the advantage that the cost can be reduced, but the detection sensitivity differs in different directions, that is, it has direction dependency. Become.

[0005] Here, the direction dependency means the degree to which the response of the measuring element differs depending on the contact location of the contact portion when the measurement section at the tip of the stylus comes into contact with the object to be measured. Where the contact portion touched the DUT, that is, the sensitivity differs depending on the contact orientation, so even if there is contact orientation dependence, where in the contact portion contacted the DUT,
That is, if the contact azimuth can be specified, the sensitivity can be corrected. In Conventional Example 1, although the measuring elements are divided into those for X-axis measurement and those for Y-axis measurement, no further consideration is given to the direction dependence. Similarly, in Conventional Example 2,
Direction dependence is not considered.

That is, in the conventional examples 1 and 2, the contact azimuth is not specified, and the sensitivity is not corrected. In Conventional Example 3, the sum of the absolute values of the signals output from the plurality of piezoelectric elements is calculated so that the detection sensitivity when the tip of the stylus comes into contact with the object to be measured does not have directivity. However, in the case where the device comes into contact with the object to be measured from a direction perpendicular to the stylus axis, the direction dependency of the detection sensitivity is not sufficiently improved. No mention is made of the case of contact from the stylus axis direction.

An object of the present invention is to provide a touch signal probe which has a simple structure and has no direction dependency.

[0008]

Therefore, according to the present invention, a piezoelectric element for detection is mounted on a side surface of a piezoelectric element supporting portion of a regular polygonal body, and output signals output from these piezoelectric elements for detection are processed according to a predetermined process. It is intended to achieve the above object by performing arithmetic processing.

Specifically, the touch signal processor according to the present invention
The probe is a column with a contact part at the tip that comes into contact with the object to be measured.
The stylus in contact with the object to be measured
Signal signal with a detection piezoelectric element
The stylus includes the detecting piezoelectric element.
A piezoelectric element support portion for supporting and fixing the piezoelectric element.
The cross section orthogonal to the axis of the stylus is positive n.
(N = 3, 4 ...) is a regular polygonal body that is a square,
The detection piezoelectric element is provided on each side of the regular polygonal body.
Attach at least one of these detecting piezoelectric elements
Changes in the output signal output from the piezoelectric element
A contact detection circuit for detecting contact and
Output signal S output from all elements₁, S_Two, S_Three,…, S_nSum of
And a first addition circuit for determining
A first amplifier circuit for multiplying the sum by (1 / n)
No. of averages (S_1HA) an average value calculating circuit for determining
After the detection circuit detects the contact,
Within a predetermined time determined by the natural frequency of the
The voltage E at which the absolute value of the output of the first amplifier circuit becomes maximum _1HTo
A first peak hold circuit for holding, and the detecting piezoelectric element
Output signal S output from child₁, S_Two, S_Three,…, S_nAnd the first increase
Output S of width circuit_1HA first subtraction circuit for determining the difference between
After the contact detection circuit detects a contact, the stylus shaft
Determined by the natural frequency of vibration in the direction orthogonal to
Within a fixed time, the absolute value of the output of the first subtraction circuit is minimized.
High voltage (E_1v, E_2v,…, E_nv)
And the first peak hold circuit.
The held voltage (E_1H) And the second peak hold circuit
The held voltage (E_1v, E_2v,…, E_nv)
The direction and speed of contact between the touching part and the object
And a contact state detecting circuit for outputting the contact state.

For the measurement, when the contact portion of the stylus comes into contact with the object to be measured by moving the touch signal probe of the present invention, the contact is detected by a contact detection circuit, and the impact force at the time of the contact is detected by each of the detecting piezoelectric elements. Output from These output signals are arithmetic processing, first, the signal S _1, S _2, S ₃ output from the detecting piezoelectric element, ..., as well as calculating the sum of S _n in the first addition circuit, the sum Is multiplied by (1 / n) in the first amplifier circuit to obtain the average (S _1H ) of the output signal. The reason why the average value is obtained by summing the output signals is to remove a bending distortion component acting on the stylus axis and extract a longitudinal distortion component acting in the stylus axis direction. Further, the output signal S ₁ output from the detecting piezoelectric element, S _2, S _3, ..., the output of the and S _n the first amplifier circuit (S _IH) difference between the (S _nV) the first subtraction circuit Ask for. The reason for obtaining these differences is to extract a transverse distortion component acting in a direction orthogonal to the stylus axis.

Thereafter, the voltage (E _1H ) at which the absolute value of the output of the first amplifier circuit becomes maximum is held by the first peak hold circuit, and the voltage (E _1H ) at which the absolute value of the output of the first subtraction circuit becomes maximum ( E _1v , E _2v ,..., _{En v} ) are held by the second peak hold circuit. The azimuth and speed at which the contact portion comes into contact with the object to be measured are determined by the voltage (E _1H ) and the voltages (E _1v , E _2v ,..., _Env ) held by these peak hold circuits. Detected by the detection circuit. Therefore, in the present invention,
By processing the signal output from each detecting piezoelectric element, highly accurate measurement can be performed without directional dependency.
Further, since the detection piezoelectric element is attached to the side surface of the polygon, the structure of the touch signal probe can be simplified.

Here, in the present invention, the contact state detection circuit squares the voltage (E _1v , E _2v ,..., _Env ) held by the second peak hold circuit to (E _1v ² , E _2v ² ,…, E
_nv ² ) and the sum (E _1v ² + E _2v ² +... +) of the outputs (E _1v ² , E _2v ² ,..., E _nv ² ) of the first multiplier.
_Env ² ), a second amplifying circuit for multiplying the output (E _1v ² + E _2v ² +... + E _nv ² ) of the second adding circuit by (1 / n), and a second amplifying circuit Circuit output ｛(E _1v ² +
^{_{E 2v 2 + ... + E nv}} 2) / n} a first arithmetic circuit for obtaining a square root of said second voltage held by the peak hold circuit _{(E 1v, E 2v, ...} , E n v) the first A first division circuit for calculating a ratio with respect to an output of an arithmetic circuit; and an arc cosine of an output of the first division circuit for calculating an arc cosine between the contact portion and the device under test in a plane orthogonal to the axial direction of the stylus. And a second arithmetic circuit for determining the contact azimuth β. In this configuration, since the contact azimuth β can be reliably calculated, the contact azimuth β can be specified and the sensitivity can be corrected by a predetermined method, so that highly accurate measurement can be performed.

On the other hand, when the piezoelectric element supporting portion is a regular quadrilateral, the contact state detecting circuit is provided with the second
The voltage (E _1v ) (E
_2v ), and a fourth division circuit for calculating the ratio (E _1v / E _2v ), and calculating the arc tangent of the output of the fourth division circuit to contact the contact portion in a plane perpendicular to the axial direction of the stylus with the object. A fourth arithmetic circuit for determining a contact direction β with the object;
May be provided. With this configuration, the contact azimuth β can be reliably calculated with a simple configuration as compared with the above-described configuration.

Further, the contact state detecting circuit is provided with
The voltage (E) held by one peak hold circuit_1H) Prescribed
A third amplifying circuit for amplifying to the magnification of
Voltage (E_1v, E_2v,…, E_nv) To 2
And take (E_1v ^Two, E_2v ^Two,…, E_nv ^Two) To find the first multiplier
And the output of this first multiplier (E_1v ^Two, E_2v ^Two,…, E_nv ^Two)
The sum of (E_1v ^Two+ E_2v ^Two+ ... + E_nv ^Two2nd addition round for finding)
Path and the output (E_1v ^Two+ E_2v ^Two+ ... + E
_nv ^Two) Is multiplied by (1 / n), and the second amplifier circuit
Output of width circuit ｛(E_1v ^Two+ E_2v ^Two+ ... + E_nv ^Two) / N｝
A first arithmetic circuit for obtaining a square root;
A second division for determining the ratio of the force to the output of the first arithmetic circuit
And the arc tangent of the output of this second division circuit
The contact portion and the contact portion are calculated in a plane including the stylus axis.
A third arithmetic circuit for determining a contact direction α with the object to be measured.
The configuration described above may be used. In this configuration, the contact direction α
Can be calculated, specify contact azimuth α and specify
The sensitivity can be corrected by the method of
You.

[0015] The contact state detection circuit may be configured to detect the first state.
The voltage held by the peak hold circuit (E_1HGiven)
A third amplifying circuit for amplifying the magnification K, and a third amplifying circuit
A third multiplying circuit for squaring the output, and the second peak hall
Voltage (E _1v, E_2v,…, E_nv) Squared
(E_1v ^Two, E_2v ^Two,…, E_nv ^Two) To find the first multiplier
And the output of this first multiplier (E_1v ^Two, E_2v ^Two,…, E_nv ^Two)
The sum of (E_1v ^Two+ E_2v ^Two+ ... E_nv ^Two) To find the second addition circuit
And the output (E_1v ^Two+ E_2v ^Two+ ... + E_nv
^Two) Multiplied by (1 / n), and the third multiplication circuit
A second circuit for calculating a sum of an output of the circuit and an output of the second amplifier circuit;
A third adder circuit and the square root of the third adder circuit are calculated and
Proportional to the speed V at which the contact part comes into contact with the object to be measured
And a third arithmetic circuit for determining the amount of
No. In this configuration, an amount proportional to the contact speed V is reliably performed.
Can be calculated, so it is proportional to the stylus contact speed
Since the sensitivity can be corrected by a predetermined method by specifying the amount to be
Highly accurate measurement can be performed.

[0016]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1A shows the entire configuration of a touch signal probe according to one embodiment of the present invention. In FIG. 1A, the touch signal probe of the present embodiment has a structure in which a plurality of piezoelectric elements 2 are attached to a substantially column-shaped stylus 1 having a spherical contact portion 1A at the tip thereof for contacting an object to be measured. The stylus 1 includes the contact portion 1A, a stylus body 1B having a circular cross section with the contact portion 1A attached to one end, and a stylus body 1
B, a piezoelectric element supporting portion 1C integrally formed at the other end portion, and a screw portion 1D provided at an end portion of the piezoelectric element supporting portion 1C and attached to a probe main body (not shown). Are located in

The piezoelectric element supporting portion 1C is a regular polygon whose cross section orthogonal to the stylus axis is a regular n (n = 3, 4...) Polygon, and the piezoelectric element 2 is provided on each side surface of the regular polygon.
₁ , 2 ₂ , 2 ₃ ... 2 _n are fixed with an adhesive or the like on the entire surface. For example, the piezoelectric element support 1C is
As shown in FIG. 1 (B), it may be a cross-section an equilateral triangle, in this case, the piezoelectric element 2 ₁ to 2 ₃ is secured to its respective side surface. Furthermore, the piezoelectric element support part 1C, as shown in FIG. 1 (C), may be a square cross-section, in this case, the piezoelectric elements ₂₁ to ₂₄ are fixed to the respective side. Of these, the piezoelectric elements 2 _1, 2 ₃ is in the front and back relationship to each other across the piezoelectric element support part 1C, at a position where the piezoelectric element 2 _2, 2 ₄ is adjacent to the piezoelectric element 2 _1, 2 _3, the front and back of each other In a relationship.

The object to be measured contacts the contact portion 1A of the stylus 1.
When touched, each piezoelectric element 2₁, 2_Two, 2 _Three,…, 2_nOutput signal from
No. S₁, S_Two, S_Three,…, S_nIs output. Contact part 1A is measured
Although it comes into contact with the fixed object in various contact directions, in this embodiment,
As shown in FIG. 2, in a plane including the stylus axis
Is defined as α, and in the plane orthogonal to the stylus axis
The angle is defined as β. DUT is in contact with stylus 1
1A, the piezoelectric element 2₁, 2_Two, 2_Three,…, 2_nFrom
Output signal S₁, S_Two, S_Three,…, S_nIs output.
When one piezoelectric element 21 is focused on, its output signal
Is generally a stylus shaft as shown in FIG.
Direction S perpendicular to_VFIG. 3 (B) shows the component due to the vibration of
As shown, stylus axial direction S_HOf vibration
And minutes. Therefore, the piezoelectric element 2₁Output signal
S₁And the vibration in the direction perpendicular to the stylus axis
Component S_1vAnd the component of the vibration in the stylus axis direction is
S_1HIs defined as

[0019]

(Equation 1)

## EQU1 ## _If the output signals S ₂ , S ₃ ,..., S _n of the other piezoelectric elements 2 ₂ , 2 ₃ ,.

[0021]

(Equation 2)

Can be expressed as Piezoelectric elements 2 ₁ , 2 ₂ , 2
_3, ..., 2 _n output signals S _{1 of, S 2, S 3, ...} , in S _n, component S _{1 v} due to vibration in the direction orthogonal to the stylus axis, S _2v, S
_3V, ..., S _nv is the piezoelectric element 2 _1, 2 _2, 2 _3, ..., because the sensitivity of the 2 _n is directional dependence and the sum,

[0023]

(Equation 3)

## EQU1 ## That is, each piezoelectric element 2 ₁ , 2 ₂ , 2 ₃
...... 2 _n, because they are spaced apart a predetermined angle from each other about the stylus axis, the piezoelectric element _{2 1, 2 2, 2 3} ...... 2 n in the front and back relationship to each other across the stylus shaft, an output The components S _1v , S _2v , S _3V ,..., S _{nv of the} signal due to vibration in the direction perpendicular to the stylus axis have opposite values, and are canceled out as a whole. In the output signals of the piezoelectric elements 2 ₁ , 2 ₂ , 2 ₃ ... 2 _n , components S _1H ,
_{S 2H, S 3H, ...... S} nH , since there is no directional dependence on the sensitivity of the piezoelectric element _{2 1, 2 2, 2 3} ...... 2 n,

[0025]

(Equation 4)

## EQU1 ## Therefore, it calculates the sum of the S ₁ to S _n, when divided by n,

[0027]

(Equation 5)

Thus, the component due to the vibration in the stylus axis direction can be extracted. Also, the component due to the vibration in the direction orthogonal to the stylus axis is

[0029]

(Equation 6)

It can be extracted from the following equation. FIG.
It is a graph showing in detail the temporal change of the component S _{1 v} due to vibration in the direction orthogonal to the stylus axis of the piezoelectric element 2 ₁ of the output signal obtained from the equation. FIG. 4 shows that the vibration component S _1v in the direction orthogonal to the stylus axis takes a local maximum value E _1v at time T _v determined by the natural frequency in the direction orthogonal to the stylus axis. Since the maximum value E _1v may be a negative voltage depending on the contact direction β, the maximum value E _1v is defined as a voltage at which the absolute value of S _1v becomes maximum during a certain time after the contact. E _2V ,…, E _nv also E _1v
Is defined similarly. If the contact speed is constant, the sensitivity of the piezoelectric element has direction dependency, so E _1v ,
E _2v , E _3v ,..., _{En nv} change as shown in FIG. The maximum value A _r of the voltage E _{1 v} is proportional to the velocity V at the time of contact. This is because the magnitude of the output signal which the contact part 1A is output from the piezoelectric element 2 ₁ in proportion to the impact force when contacting the workpiece (voltage) increases. Furthermore, the maximum value A _r of the voltage E _{1 v} is dependent on the contact direction alpha. That is,
Contact azimuth α although increases maximum A _r of smaller if the voltage E _{1 v,} the maximum value A _r of the voltage E _{1 v} greater contact azimuth α
Becomes smaller.

[0031] FIG. 6 is a graph showing the temporal change of the vibration component S _IH stylus axial detail of the piezoelectric element 2 ₁ of the output signal obtained from the equation. In FIG. 6, a maximum value E _1H is obtained at a time T _{H at} which the vibration component S _1H in the stylus axis direction is determined by the natural frequency and the like in the stylus axis direction.
Is taken. This maximum value E _{1H is} also the maximum value E
Similarly to _1v, it is defined as a voltage at which the absolute value of S _1H is maximized during a certain time after the contact. Speed V at the time of contact
Is constant, the maximum value E _1H and the voltage E
The maximum value A _r of _1v changes as shown in FIG. That is, in FIG. 7, the local maximum value E _1H of the vibration component S _{1H in} the stylus axis direction increases as the contact direction α changes from 0 degree to 90 degrees.
Although increases, conversely, the maximum value A _r of the voltage E _{1 v} of the vibration component S _{1 v} in the direction orthogonal to the stylus axis decreases. Further, if the contact direction is constant, it is proportional to both the velocity V and the maximum value A _r of the voltage E _IH and the voltage E _{1 v.}

Here, K _v : a stiffness in a direction orthogonal to the axis of the stylus, a constant determined by the same-direction sensitivity of the piezoelectric element, and K _H : a constant determined by an axial stiffness of the stylus, the same-direction sensitivity of the piezoelectric element, and the like. , Φi: _Assuming that the phase difference from _E1v determined by the arrangement of the piezoelectric elements (φi = 360 (i−1) / n), the following equation can be obtained.

[0033]

(Equation 7)

According to the above process, the piezoelectric elements 2 ₁ , 2
₂ ,..., 2 _n the contact directions α and β of the output signals output from _n
, An amount proportional to the speed V can be detected. A block diagram of the output signal generation device is shown in FIG. 8, the piezoelectric element 2 _1, 2 _2, ..., the output signal is outputted from the 2 _n S _1, S _2, ..., S _n, the sum (S ₁ + S ₂ + ...
+ S _n ) is calculated by the first adder circuit 31, and the sum is calculated as the first
The signal is amplified (1 / n) times by the amplifier circuit 32.

The first addition circuit 31 and the first amplification circuit
From the path 32 to the piezoelectric element 2₁, 2_Two,…, 2 _nOutput from all of
Output signal S₁, S_Two... S_nAverage (S_1H) From a formula
An average value calculation circuit 33 for calculating the average value is configured. Piezoelectric element 2₁,
2_Two,…, 2_nOutput signal S output from₁, S_Two... S_nAnd the first
Output S of amplifier circuit 31_1HIs reduced by the first value based on the formula.
The arithmetic processing is performed by the arithmetic circuit 34. Thereby, the output signal S₁,
S_Two... S_nComponent oscillating in the direction perpendicular to the stylus axis
S _1v, S_2v,…, S_nvCan be extracted.

The piezoelectric element 2 _1, 2 _2, ..., 2 at least a portion of the detecting piezoelectric elements of _n 2 _1, 2 _2, ..., the output signal is outputted from the 2 _n S _1, S _2, ......, _Sn is sent to a contact detection circuit 35, which outputs output signals S ₁ , S ₂ ,.
Are those amplitude of S _n, frequency, capture the change of phase such as the contact portions 1A of the stylus 1 detects that the contact with the object to be measured, its specific configuration is, Ya Japanese Patent Application No. 8-146709 It is shown in Japanese Patent Application No. 8-164710.

[0037] After the contact detection circuit 35 detects the contact, the output until a certain time T _H has elapsed determined by the natural frequency of axial stylus 1 of the first amplifier circuit 32 S
_The voltage E _{1H at} which the absolute value of _1H becomes the maximum is held by the first peak hold circuit 36, and after the contact detection circuit 35 detects the contact, it is determined by the natural frequency of vibration in the direction orthogonal to the axis of the stylus 1 and the like. and the output S _{1 v} of the first subtraction circuit 34 until a predetermined time T _v elapsed, S _2v, ..., the voltage absolute value is maximum of _{S nv (E 1v, E 2v} , ..., E nv) the It is held by the second peak hold circuit 37. The voltage E _1H and the voltage (E _1v , E _2v) held by these peak hold circuits 36 and 37 are
.. E _nv ), the contact state detection circuit 38 detects the azimuth αβ and the velocity V when the contact portion 1A of the stylus 1 contacts the object to be measured.

FIG. 9 shows a specific configuration of the contact state detection circuit 38. FIG. 9 is a block diagram of the contact state detection circuit 38. In FIG. 9, the contact state detection circuit 38
Is a contact part 1 in a plane orthogonal to the axial direction of the stylus 1.
A first multiplication circuit 41 for squaring the voltage held by the second peak hold circuit 37 to calculate a contact azimuth β between A and the device under test, and a second multiplication circuit for calculating the sum of the outputs of the first multiplication circuit 41 A second adder circuit 42; a second amplifier circuit 43 for multiplying the output of the second adder circuit 42 by (1 / n); a first arithmetic circuit 44 for calculating the square root of the output of the second amplifier circuit 43; The voltage E1v held by the peak hold circuit 37 and the first
First division circuit 45 for obtaining a ratio with the output of operation circuit 44
And a second operation circuit 46 for calculating the arc cosine of the output of the first division circuit 45.

In the first multiplication circuit 41, the voltages (E _1v , E _2v ,
, E _nv ) are squared to obtain (E _1v ² , E _nv )
_2v ² ,..., _Env ² ). The second arithmetic circuit 42 adds (E _1v ² + E _2v ² +...)
+ E _nv ² ). In the second amplifier circuit 43, the second
The value (E _1v ² + E _2v ² +... + E _nv) obtained by the addition circuit 42
² ) times (1 / n). In the first operation circuit 44, the square root of the value obtained in the second amplification circuit 43 is obtained.

[0040]

(Equation 8)

Is required. This value is the maximum value Ar of the voltage _E1v . In the first division circuit 45, the voltages (E _1v , E _2v ... + E _nv ...) Held in the second peak hold circuit 37
When determining the ratio (E _{1 v} / A _r) of the output A _r of the first arithmetic circuit 44. The second operation circuit 46, the plane perpendicular to the arc cosine (Cos ^-1 (axial E _1v / A _r) and by calculating the stylus first output (E _1v / A _r) of the first divider circuit 45 The contact direction β between the contact portion 1A and the object to be measured is determined.

The contact state detecting circuit 38 controls the stylus axis.
The contact azimuth α between the contact part 1A and the DUT in the plane
The voltage held by the first peak hold circuit 36
Pressure (E_1H) To a predetermined magnification K.
And the voltage (E) held by the second peak hold circuit 37.
_1v, E_2v,…, E_nv) Squared (E)_1v ^Two, E_2v ^Two,…,
E_nv ^Two), And the first multiplier 41
The output (E_1v ^Two, E_{Two v} ^Two,…, E_nv ^Two) Sum (E_1v
^Two+ E_2v ^Two+ ... + E_nv ^Two), A second addition circuit 42 for determining
The output (E_1v ^Two+ E_2v ^Two+ ... + E_nv
^Two) Is multiplied by (1 / n), and the second amplifier 43
The output 増 幅 (E_1v ^Two+ E_2v ^Two+ ... + E_nv ^Two) /
a first arithmetic circuit 44 for calculating the square root of n｝, and a third amplification circuit
Output of road 51 (K × E_1H) And the output of the first arithmetic circuit 44
And a second division circuit 52 for calculating the ratio of
A third arithmetic circuit for calculating the arc tangent of the output of 2
53.

In the third amplifier circuit 51, the voltage (E _1H ) is set to a predetermined magnification K, where K = (K _v / K _H ). This is due to the rigidity of the stylus 1 and the piezoelectric elements 2 ₁ , 2
Due to the sensitivity direction dependence of ₂ ,..., 2 _n , K _v
Unlike common to the K _H, therefore, by the maximum value of the maximum value and A _v of E _IH it is different, as shown these values in FIG. 10, in order to equalize. The third arithmetic circuit 53 calculates the arc tangent (tan ^-1 {(K * E _1H ) / A _v } of the ratio between the output (K × E _1H ) of the third amplifier circuit 51 and the output of the first arithmetic circuit 44. By calculating this value, the contact azimuth α between the contact portion 1A and the object to be measured is determined in a plane including the stylus axis.

The contact state detection circuit 38 obtains the voltage (E) held by the first peak hold circuit 36 in order to obtain an amount proportional to the speed V when the contact portion 1A comes into contact with the object to be measured.
_1H ) to a predetermined magnification K, and a third multiplier circuit 61 for squaring the output of the third amplifier circuit 51.
And the voltage held by the second peak hold circuit 37 is 2
A first multiplication circuit 41 for multiplying the first multiplication circuit 41, a second addition circuit 42 for obtaining the sum of the outputs of the first multiplication circuit 41, and a second amplification circuit 43 for multiplying the output of the second addition circuit 42 by (1 / n). , A third addition circuit 62 for calculating the sum of the output of the third multiplication circuit 61 and the output of the second amplification circuit 43, and a third calculation circuit 63 for calculating the square root of the output value of the third addition circuit 62. Configuration. In the third multiplication circuit 61, the voltage (E _1H ) is
{K × (E _1H )} 2 is obtained by squaring the doubled value. In the third adding circuit 62, (KE _1H ) ² + (A _r ) ² is obtained. In the third arithmetic circuit 63, ｛(KE _1H ) ² +
(A _r ) ² ｝ ^1/2 is required. By obtaining this value, an amount proportional to the speed V is detected.

Therefore, in this embodiment, the object to be measured is
Column-shaped stylus 1 having a contact portion 1A that comes into contact with the stylus
Then, a detection for detecting that the contact portion 1A has come into contact with the object to be measured.
Outgoing piezoelectric element 2₁, 2_Two, 2_Three,…, 2_nPlace this style
The lath 1 is a piezoelectric element 2 for detection.₁, 2_Two, 2_Three,…, 2_nSupport solid
Element supporting portion 1C for fixing the piezoelectric element.
The cross section orthogonal to the axis of the stylus 1 is positive n.
(N = 3, 4 ...) is a regular polygonal body that is a square,
Detecting piezoelectric elements 2 on each side of the regular polygon₁, 2_Two, 2 _Three,
…, 2_nRespectively, and these detecting piezoelectric elements 2
₁, 2_Two, 2_Three, ……, 2_nAt least some of the piezoelectric
Element 2₁, 2_Two, 2_Three,…, 2_nOutput signal S output from₁, S
_Two, S_Three,…, S_nContact detection that detects changes by capturing changes in contact
Circuit 35 and piezoelectric element 2 for detection₁, 2_Two, 2_Three,…, 2_nAll of
Output signal S output from₁, S_Two, S_Three,…, S_nFind the sum of
The first addition circuit 31 and the first addition circuit 31
Having a first amplifier circuit 32 for multiplying the sum by (1 / n)
Signal average (S_1H) Is calculated.
After the touch detection circuit 35 detects the contact, the axis of the stylus 1
Within a predetermined time determined by the natural frequency of the direction, etc.
The voltage E at which the absolute value of the output of the first amplifier circuit 32 becomes maximum.
_1HA first peak hold circuit 36 for holding the
Electric element 2₁, 2_Two, 2_Three,…, 2_nOutput signal S output from₁,
S_Two, S_Three,…, S_nAnd the output S of the first amplifier circuit 32_1HAnd the difference
The first subtraction circuit 34 and the contact detection circuit 35 determine the contact.
After detection, the vibration fixed in the direction orthogonal to the axis of stylus 1 is fixed.
First reduction within a predetermined time determined by the vibration frequency, etc.
The voltage (E at which the absolute value of the output of the_1v, E
_2v,…, E_nv) To hold the second peak hold circuit 37
And the voltage (E) held by the first peak hold circuit 36.
_1H) And the voltage held by the second peak hold circuit 37
(E_1v, E_2v,…, E_nv), The contact portion 1A and the DUT
Contact state detection that detects the direction and speed of contact with
Circuit 38, each detecting piezoelectric element 2₁, 2_Two, 2
_Three,…, 2_nOutput signal S output from₁, S_Two, S_Three,…, S_nof
The sum is calculated by the first adder circuit 31, and this sum is
Multiplied by (1 / n) in one amplifier circuit 32 and averaged (S)
_1H), The bending acting on the stylus axis
Longitudinal distortion component acting in the stylus axis direction by removing the distortion component
Can be extracted, and the detection piezoelectric element 2₁, 2
_Two, 2_Three, ……, 2_nOutput signal S output from₁, S_Two, S_Three,
…, S_nAnd the output of the first amplifier circuit 32 (S_1H) And difference
(S_nv) In the first subtraction circuit 34,
Extract the transverse distortion component acting in the direction orthogonal to the Iras axis
High-precision measurement without directional dependence
Can be set. In addition, a piezoelectric element for detection is placed on the side of the polygon.
2₁, 2_Two, 2_Three, ……, 2_nTo attach
The structure of the switch signal probe can be simplified.

Further, in the present embodiment, the contact state detection time
The path 38 is connected to the power held by the second peak hold circuit 37.
Pressure (E_1v, E_2v,…, E_nv) Squared (E)_1v ^Two, E_2v ^Two,…,
E_nv ^Two), And the first multiplication circuit 41
Output of road 41 (E_1v ^Two, E_2v ^Two,…, E_nv ^Two) Sum (E_1v ^Two+
E_2v ^Two+ ... + E_nv ^Two), And a second addition circuit 42
The output of the second adding circuit 42 (E_1v ^Two+ E_2v ^Two+ ... + E_nv ^Two)
A second amplification circuit 43 that multiplies the second amplification by (1 / n)
The output ｛(E_1v ^Two+ E_2v ^Two+ ... + E_nv ^Two) / N｝
A first arithmetic circuit 44 for calculating the square root of
Voltage (E) held by the_1v, E_2v,…, E_nv)
Division circuit for calculating the ratio of the output of the first operation circuit 44
45 and the arc cosine of the output of the first division circuit 45
And calculate the tangent in a plane orthogonal to the axial direction of the stylus 1.
Second calculation cycle for determining the contact direction β between the touch unit 1A and the object to be measured
Path 46, the contact azimuth β is reliably calculated.
Specified contact azimuth β and sensitivity by a predetermined method
By performing the correction, highly accurate measurement can be performed.

Further, the contact state detection circuit 38 is connected to the first pin
The voltage (E) held by the_1H) Prescribed
A third amplification circuit 51 that amplifies the signal to a magnification of
Voltage (E) held by the_1v, E_2v,…, E_nv)
Squared (E_1v ^Two, E_2v ^Two,…, E_nv ^TwoFirst multiplication to find
Circuit 41 and the output (E_1v ^Two, E_{Two v}
^Two,…, E_nv ^Two) Sum (E_1v ^Two+ E_2v ^Two+ ... + E_nv ^Two)
A second addition circuit 42 and an output of the second addition circuit 42
(E_1v ^Two+ E_2v ^Two+ ... + E_nv ^Two) Multiplied by (1 / n)
Amplifying circuit 43 and the output ｛(E_1v
^Two+ E_2v ^Two+ ... + E_nv ^TwoThe first performance to find the square root of) / n｝
Arithmetic circuit 44, the output of the third amplifier circuit 51, and the first arithmetic circuit
A second division circuit 52 for obtaining a ratio with respect to the output of the second
By calculating the arc tangent of the output of the divide-by-2 circuit 52
In the plane including the stylus axis, the contact portion 1A and the DUT
And a third arithmetic circuit 53 for determining the contact direction α.
The contact direction α can be reliably calculated, and the contact direction α
By identifying and correcting sensitivity in a predetermined way, accuracy
High measurement.

The contact state detecting circuit 38 includes a third amplifying circuit 51 for amplifying the voltage (E _1H ) held by the first peak hold circuit 36 to a predetermined magnification K, and an output of the third amplifying circuit 51. , The first multiplication circuit 41 squaring the voltage held by the second peak hold circuit 37, and the second addition circuit 42 for obtaining the sum of the outputs of the first multiplication circuit 41 A second amplification circuit 43 for multiplying the output of the second addition circuit 42 by (1 / n), and a third multiplication circuit 6
A third method for calculating the sum of the output of the second amplifier circuit 43 and the output of
Since there is provided an addition circuit 62 and a third calculation circuit 63 for calculating the square root of the third addition circuit 62 to obtain an amount proportional to the speed V when the contact portion 1A comes into contact with the device under test, the contact speed An amount proportional to V can be reliably calculated, and a high-precision measurement can be performed by specifying an amount proportional to the contact speed V and correcting the sensitivity by a predetermined method.

The present invention is not limited to the above-described embodiment, but includes the following modifications as long as the object of the present invention can be achieved. For example, in the present invention, when the piezoelectric element supporting portion 1C is a regular square, FIG.
As shown in FIG. 1, the contact state detection circuit 38 is held by the second peak hold circuit 37 in order to obtain the contact direction β between the contact portion 1A in a plane orthogonal to the axial direction of the stylus 1 and the object to be measured. Voltage (E _1v ) (E _2v ) ratio (E _1v / E
_2v ), and the fourth division circuit 7
And a fourth arithmetic circuit 72 for calculating the arc tangent of the first output. In the fourth operation circuit 72, the arc tangent (tan ^-1 ( _E1v / _E2v )) of the output ( _E1v / _E2v ) of the fourth division circuit 71 is obtained. By obtaining this value, the contact direction β is detected. Therefore, in this configuration, the contact azimuth β can be reliably calculated with a simple configuration as compared with the above-described configuration.

In the present invention, the piezoelectric element 2₁, 2_Two, 2_Three,
............ 2_nPiezo element support to increase output from
The central portion of the portion 1C is formed so as to be narrowed, and the piezoelectric element 2₁, 2
_Two, 2 _Three, ……, 2_nHas both ends on the piezoelectric element support 1C.
Supported and fixed, the center of which is between the piezoelectric element support 1C
May be used to form a gap. In this structure, the piezoelectric
Since the rigidity of the element supporting portion 1C is reduced, the piezoelectric element 2
₁, 2_Two, 2_Three, ……, 2_nIncreases the amount of deformation. Therefore, the pressure
Electric element 2₁, 2_Two, 2_Three, ……, 2_nOutput becomes large,
Measurement accuracy can be improved.

[0051]

As described above, according to the present invention, the detection piezoelectric element for detecting that the contact portion has come into contact with the object to be measured is provided on the substantially column-shaped stylus having the contact portion at the tip which comes into contact with the object to be measured. The stylus has a piezoelectric element support for supporting and fixing the detection piezoelectric element, and the cross section of the piezoelectric element support perpendicular to the axis of the stylus is positive n (n = 3,4...) Is a regular polygon having a rectangular shape, and a detection piezoelectric element is attached to each side surface of the regular polygon, and at least a part of the detection piezoelectric elements is used for detection. A contact detection circuit for detecting a contact by capturing a change in an output signal to be output, a first addition circuit for obtaining a sum of output signals output from all of the detection piezoelectric elements, and a sum obtained by the first addition circuit Times (1 / n) times An average value calculating circuit for calculating an average of output signals having a first amplifying circuit, and a first amplifying circuit within a predetermined time determined by an axial natural frequency of the stylus after the contact detecting circuit detects a contact. A first peak hold circuit for holding a voltage at which the absolute value of the output of the circuit is maximized;
A first subtraction circuit for obtaining a difference from an output of the amplifier circuit; and a first subtraction within a predetermined time determined by a natural frequency of vibration in a direction orthogonal to an axis of the stylus after the contact detection circuit detects a contact. A second peak hold circuit for holding a voltage at which the absolute value of the output of the circuit is maximum, and a contact portion and an object to be measured by the voltage held by the first peak hold circuit and the voltage held by the second peak hold circuit And a contact state detection circuit for detecting the azimuth and speed at which the contact is made, the sum of the output signals output from the respective detection piezoelectric elements is calculated by the first addition circuit, and this sum is subjected to the first amplification. By calculating the average of the output signal by multiplying the output signal by (1 / n), the bending distortion component acting on the stylus axis can be removed and the longitudinal distortion component acting on the stylus axis can be extracted. Pressure By obtaining the difference between the output signal output from the electric element and the output of the first amplifier circuit by the first subtraction circuit, it is possible to extract a transverse distortion component acting in a direction orthogonal to the stylus axis. Therefore, it is possible to detect the contact position between the contact portion and the object to be measured, that is, the contact direction, using the longitudinal distortion component and the lateral distortion component. And high-accuracy measurement becomes possible. Further, in the measurement by a coordinate measuring machine or the like, when the measurement direction can be predicted from the direction of movement of the probe, there is an advantage that erroneous measurement can be confirmed by comparison with the actual contact direction by the above-described method. Further, since the detection piezoelectric element is attached to the side surface of the polygon, the structure of the touch signal probe can be simplified.

[Brief description of the drawings]

FIGS. 1A and 1B show a touch signal probe according to an embodiment of the present invention, in which FIG. 1A is a front view, FIG. 1B is a cross-sectional view in the case where a piezoelectric element support is a regular triangle, and FIG. FIG. 4 is a cross-sectional view when the piezoelectric element support is square.

FIG. 2 is a perspective view of a contact portion for explaining a contact direction αβ.

FIG. 3A is a front view of a stylus for explaining that a vibration direction is a direction orthogonal to a stylus axis, and FIG. 3B is a view for explaining that a vibration direction is a stylus axis direction. It is a front view of a stylus.

FIG. 4 is a graph showing in detail a temporal change of a component of an output signal of a piezoelectric element due to vibration in a direction orthogonal to a stylus axis.

FIG. 5 is a graph showing a relationship between a voltage of an output signal output from a piezoelectric element and a contact direction β.

FIG. 6 is a graph showing in detail a temporal change of a vibration component in a stylus axis direction in an output signal of a piezoelectric element.

FIG. 7: Contact direction α and vibration component S _{1H in the} stylus axis direction
_Is a graph showing a relationship between a maximum value E _1H of the vibration component S _1v and a maximum value Ar of a voltage E _1v of a vibration component S _{1v in} a direction orthogonal to the stylus axis.

FIG. 8 is a block diagram showing an output signal generation device of the embodiment.

FIG. 9 is a block diagram illustrating a contact state detection circuit.

FIG. 10 is a graph for explaining amplifying a voltage (E _1H ) held by a first peak hold circuit to a predetermined magnification K;

FIG. 11 is a block diagram showing a modification (an example in which a contact state detection circuit is different) of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Stylus 1A Contact part 1C Piezoelectric element support part 21,22,23, ..., 2n Piezoelectric element 31 1st addition circuit 32 1st amplification circuit 33 Average value calculation circuit 35 Contact detection circuit 36 1st peak hold circuit 37 2nd peak Hold circuit 38 Contact state detection circuit 41 First multiplication circuit 42 Second addition circuit 43 Second amplification circuit 44 First operation circuit 45 First division circuit 46 Second operation circuit 51 Third amplification circuit 52 Second division circuit 53 Third Operation circuit 61 Third multiplication circuit 62 Third addition circuit 63 Fourth operation circuit 71 Fourth division circuit 72 Fourth operation circuit

Claims (5)

[Claims] 1. A touch signal probe comprising: a substantially columnar stylus having a contact portion at a tip thereof for contacting an object to be measured; and a detection piezoelectric element for detecting that the contact portion comes into contact with the object to be measured. The stylus has a piezoelectric element support for supporting and fixing the detection piezoelectric element. The piezoelectric element support has a regular n (n = 3, 4,...) Square cross section orthogonal to the axis of the stylus. The detection piezoelectric element is attached to each side surface of the regular polygon, and changes in output signals output from at least some of the detection piezoelectric elements are detected. A contact detection circuit for capturing and detecting a contact; a first addition circuit for obtaining a sum of output signals output from all of the detection piezoelectric elements; and a sum obtained by this first addition circuit multiplied by (1 / n). First increase An average value calculation circuit having a width circuit for obtaining an average of the output signal; and a first time period within a predetermined time determined by an axial natural frequency of the stylus after the contact detection circuit detects a contact. A first peak hold circuit for holding a voltage at which the absolute value of the output of the amplifier circuit is maximum, and a first subtraction circuit for calculating a difference between an output signal output from the detection piezoelectric element and an output of the first amplifier circuit After the contact detection circuit detects a contact, the absolute value of the output of the first subtraction circuit becomes maximum within a predetermined time determined by the natural frequency of vibration in a direction orthogonal to the axis of the stylus. A second peak hold circuit for holding a voltage, and the contact portion and the device under test are contacted by a voltage held by the first peak hold circuit and a voltage held by the second peak hold circuit. Touch signal probe which is characterized in that a contact state detecting circuit for detecting the orientation and speed of the time that. 2. The touch signal probe according to claim 1, wherein the contact state detection circuit squares a voltage held by the second peak hold circuit, and an output of the first multiplication circuit. , A second amplifier circuit for multiplying the output of the second addition circuit by (1 / n), a first arithmetic circuit for determining the square root of the output of the second amplifier circuit, A first division circuit for obtaining a ratio between the voltage held by the two-peak hold circuit and the output of the first arithmetic circuit; and an arc cosine of the output of the first division circuit, which is orthogonal to the axial direction of the stylus. A touch signal probe, comprising: a second arithmetic circuit for determining a contact direction between the contact portion and the device under test in a plane. 3. The touch signal probe according to claim 1, wherein the contact state detecting circuit amplifies the voltage held by the first peak hold circuit to a predetermined magnification, and the second amplifier circuit includes: A first multiplication circuit for squaring the voltage held by the peak hold circuit, a second addition circuit for obtaining the sum of the outputs of the first multiplication circuit, and multiplying the output of the second addition circuit by (1 / n) A second amplifier circuit, a first operation circuit for obtaining a square root of an output of the second amplifier circuit, a second division circuit for obtaining a ratio between an output of the third amplifier circuit and an output of the first operation circuit, A touch signal comprising: a third arithmetic circuit that calculates an arc tangent of an output of the second division circuit to obtain a contact direction between the contact portion and the device under test in a plane including a stylus axis. probe. 4. The touch signal probe according to claim 1, wherein the contact state detecting circuit amplifies the voltage held by the first peak hold circuit to a predetermined magnification, and a third amplifier circuit that amplifies the voltage. A third multiplication circuit for squaring the output of the amplification circuit, a first multiplication circuit for squaring the voltage held by the second peak hold circuit, and a second addition circuit for calculating the sum of the outputs of the first multiplication circuit A second amplification circuit for multiplying the output of the second addition circuit by (1 / n), a third addition circuit for obtaining the sum of the output of the third multiplication circuit and the output of the second amplification circuit, A touch signal probe, comprising: a fourth arithmetic circuit that calculates a square root of a third adder circuit and obtains an amount proportional to a speed at which the contact portion and the device under test make contact with each other. 5. The touch signal probe according to claim 1, wherein the piezoelectric element support is a square, and the contact state detection circuit determines a ratio of the voltage held by the second peak hold circuit. The fourth division circuit to be obtained and the fourth division circuit
A fourth arithmetic circuit for calculating an arc tangent of an output of the dividing circuit to obtain a contact direction between the contact portion and the device under test in a plane orthogonal to the axial direction of the stylus. Touch signal probe.